JASPER - Antarctic Peninsula, BAS-Station Rothera

Campaign Jasper (Feb. 2010, Antarctic Peninsula, BAS-Station Rothera)

The campaign was a study of boundary layer processes over Antarctic sea ice and was conducted in very close cooperation with the British Antarctic Survey (BAS). Polar5 and a BAS Twin Otter performed coordinated flights for meteorological measurements during a period of four weeks in February 2010 in Antarctica. The study addressed these subjects:

Heat and moisture flux from leads and polynias

For the energy and moisture exchange between the atmosphere and the ice covered ocean, leads and polynias play an important role. This is documented by many modelling studies, but only very few observations exist yet. Therefore we flew three missions to the Ronne Polynia, one of them together with the BAS Twin Otter to measure simultaneously the boundary layer modification and heat transfer over the polynia.

Sea ice roughness

In recent years we have developed methods to represent the surface roughness of sea ice in atmospheric models. These parameterisations have been based on measurements over moderately rough arctic sea ice and take ridge height and distribution into account. They are well proven for applications in simulations of flow situations in the northern polar ocean. To prove if they can be applied for antarctic conditions, low-level legs were flown during 5 flights over the sea ice in the Weddell Sea.

Radiation measurements over sea ice

Small variations in the reflectance of sea ice have a significant effect on the energy exchange between the atmosphere and the ice covered ocean. Uncertainties in the representation of sea ice albedo contribute considerably to the differences that still exist among state-of-the-art sea ice and climate models in predicting impacts of global warming in polar regions. Hence, during the campaign JASPER we obtained radiation measurements over the sea ice in the Weddell Sea to complement the findings from the Arctic and to investigate differences in more detail. Furthermore, two flights were flown in a close formation with the BAS Twin Otter to measure radiation above and below clouds, while the Twin Otter flew inside the cloud to record the particle structure.